help

[Newboy]

I have about a thousand pounds of alloy, I know it has a lot of shot in it. The problem is, I have to get it real hot (900) to even mold, and when I get it hot enough to cast, one side of the middle is all cracked looking. I also have some really nice alloy, 2% tin, 98% lead, which makes real nice bullets.

If I mix the good and the bad 50/50, I can make some bullets, as long as I don't go too fast (or the shrunken middle comes back).

I hate to screw up all of my good lead if my bad stuff is contaminated.

At one time, a guy on the old post said you could add salt to the alloy to get all of the bad stuff out.

Please advise.

[Bass Ackward]

I have about a thousand pounds of alloy, I know it has a lot of shot in it. The problem is, I have to get it real hot (900) to even mold, and when I get it hot enough to cast, one side of the middle is all cracked looking. I also have some really nice alloy, 2% tin, 98% lead, which makes real nice bullets.

If I mix the good and the bad 50/50, I can make some bullets, as long as I don't go too fast (or the shrunken middle comes back).

I hate to screw up all of my good lead if my bad stuff is contaminated.

At one time, a guy on the old post said you could add salt to the alloy to get all of the bad stuff out.

Please advise.

Newbie,

Shot has a larger percentage of arsenic in it than most other lead sourses. Arsenic will cause the problems you describe. I doubt that your mix is contaminated if it doesn't appear .... sludgy. Most likely you have too much arsenic that is causing you to mold too hot.

Heat is causing the rest of your problems which is why it works if you don't go too fast. Try mixing the stuff by 33/66 instead of 50/50 and cool things down and see if it makes a difference. But don't waste any more tin throwing good after bad.

If it doesn't work out then you probably have some zinc contamination and you are most likely screwed unless you can trade it to a junk yard for some percentage of a usuable product. 500 lbs of something good is better than 1000 lbs of not.

[Buckshot]

............Newboy, one of the reasons arsenic is put into shot is that it increases the surface tension. When shot is dropped it helps to form it into sphere's more rapidly as it falls. Too much arsenic in your boolit alloy will decrease it's fluidity enough so it's hard to cast details.

Never heard of the salt thing, but that doesn't mean it isn't valid. I'm neither metalurgist nor chemist so I can't say what adding salt would do.

As BA suggested, if you have some other alloy like WW I'd try thinning down the other. If the alloy is in a form like ingots I'd try 2 bad to 5 WW and see what happens. If it's okay then go 3 bad to 5 WW and so on. If the difficult alloy has enough arsenic in it to be causing trouble, it may also have a bit higher concentration of antimony too, which came in the form of chilled shot. Higher antimony levels can produce a brittle boolit and difficult casting.

...............Buckshot

[Newboy]

Thanks, guys.

I really didn't want to screw up all of the good stuff, and still end up with bad stuff.

But I really didn't want to trash it, if I could salvage it.

It sounds like most of the problems are things ya'll have seen before, due to arsenic and antimony.

[felix]

Newboy, save that shot alloy you have, and call it my "private mixer". Find a new batch of mainly straight-up lead, like pipes and roofing material, and tailor that lead with the private mixer. You are lucky indeed to have such a stash of antimony/arsenic already pre-mixed. If you don't smell garlic when you heat the private mixer at 900, your mixer does NOT have arsenic to any significant extent. ... felix

[Newboy]

Felix, Buckshot, and BA.

I thought that garlic was my wife's cooking!!!!!!

Got the chance to do my casting today. I put two ingots of my good, 2% lead/tin, with one ingot of my bad, antimony/arsenic mixture.

Very good bullets, but with a crystalline look. like looking through a window on a frosty west Texas morning.

The sprue almost cuts itself off. Maybe this is because of how Buckshot said antimony alloy is brittle?

I normally had to hold the mold against the bottom spout for good fill-out (still alot of rejects), but now it is doing well enough, that I am getting very good bullets leaving the mold on the rest (not held against the spout).


Thanks for the help!

[Buckshot]

.............Newboy, that's good that you're able to utilize your 'bad' alloy. The crystalized surface is usually indicative of a high alloy and block tempurature. However it is also tied to the alloy makeup.

http://www.fototime.com/2D536DBA57B9FA1/standard.jpg
This rather poor photo is of the Lee 358-158RF cast of WW alloy under 3 different conditions, in a 6 cavity mould. In all 3 cases the alloy temp was about 850*.

LEFT: Cast rapidly blocks cooler, dia .360". Sprueplate touched to a damp pad then the block bases were touched before refilling.

Center: Cast rapidly. Sprueplate only, touched to damp pad. Frosted surface, dia .358+".

Right: Sprue air cooled, cast as rapidly as possible. Very hot blocks. Fully crystaline surface structure. Bullet diameter .359+".

http://www.fototime.com/14622A982A0BAF6/standard.jpg
Another poor image:oops: This is a Mountain Moulds 2 cav creation for a 420gr boolit for the 43 Spanish. It was cast of pure lead with 5% tin. The 20# Lee post was set on warp factor 8 and the temp ranged from 925* with a full pot to close to an indicated 1000* per the Lyman thermometer with about 1/2 pot.

Air cooled sprue, and cast as fast as allowed. The boolits dropped with a mirror surface. The sprue cut very clean. The base doesn't appear so, but it was mirror bright also except for machine marks on the sprueplate. This bright unmarred surface is also evident from other moulds casting only lead, or lead/ tin.

Obviously the addition of antimony (or other additives) causes the frosted dull gray surface, or the somewhat brighter crystalline surface.

...................Buckshot